Re: OSPF SHAM-LINK

Post your configurations

On Tue, Mar 30, 2010 at 2:43 AM, Abiola Jewoola <biola_y2k_at_yahoo.com> wrote:

> I had already increased the cost of the back door link very high.
>
> Still the ospf is preferring to go through the back door link
>
>
> --- On *Mon, 3/29/10, Joe Astorino <jastorino_at_ipexpert.com>* wrote:
>
>
> From: Joe Astorino <jastorino_at_ipexpert.com>
>
> Subject: Re: OSPF SHAM-LINK
> To: "Abiola Jewoola" <biola_y2k_at_yahoo.com>
> Cc: "Ahmed Ejaz" <aahmedejaz_at_gmail.com>, ccielab_at_groupstudy.com
> Date: Monday, March 29, 2010, 11:10 PM
>
> Ahhh...yes well then that is a different story. Typically we see both
> remote sites configured for area 0. In your case if both the backdoor link
> and the sham-link learned routes are O IA all you should need to do is
> tweak
> the OSPF metric by manipulating cost where necessary. Just remember that
> cost is calculated by adding in the cost of your inbound link.
>
> On Tue, Mar 30, 2010 at 1:39 AM, Abiola Jewoola <biola_y2k@yahoo.com<http://mc/compose?to=biola_y2k@yahoo.com>>
> wrote:
>
> >
> >
> > Find attached the configs on my PE routers.
> >
> > The process id is the same and i also include the same domain-id . but
> the
> > routes still comes as IA. i guess because the PE routers area pairing
> with
> > CE routers with different areas.
> >
> >
> >
> > --- On *Mon, 3/29/10, Ahmed Ejaz <aahmedejaz@gmail.com<http://mc/compose?to=aahmedejaz@gmail.com>>*
> wrote:
> >
> >
> > From: Ahmed Ejaz <aahmedejaz@gmail.com<http://mc/compose?to=aahmedejaz@gmail.com>
> >
> > Subject: Re: OSPF SHAM-LINK
> > To: "Joe Astorino" <jastorino@ipexpert.com<http://mc/compose?to=jastorino@ipexpert.com>
> >
> > Cc: "Abiola Jewoola" <biola_y2k@yahoo.com<http://mc/compose?to=biola_y2k@yahoo.com>>,
> ccielab@groupstudy.com <http://mc/compose?to=ccielab@groupstudy.com>
> > Date: Monday, March 29, 2010, 9:57 PM
> >
> >
> > I guess the ospf process which you are redistributing into bgp requires a
> > domain id, that is the reason it is treating it as an IA route. Please
> add a
> > domain id on both the sides and the routes should come up as O routes
> then
> > you can modify the cost to not prefer the sham link.
> >
> > HTH
> > Ahmed
> >
> > On Tue, Mar 30, 2010 at 7:43 AM, Joe Astorino <jastorino@ipexpert.com<http://mc/compose?to=jastorino@ipexpert.com>
> <http://mc/compose?to=jastorino@ipexpert.com>
>
> > > wrote:
> >
> >> OSPF routes coming over the sham-link should be regular O routes
> >> (intra-area) and thus should be preferred over O IA routes...post your
> >> configurations something does not seem right about that.
> >>
> >>
> >>
> >> On Mon, Mar 29, 2010 at 10:35 PM, Abiola Jewoola <biola_y2k@yahoo.com<http://mc/compose?to=biola_y2k@yahoo.com>
> <http://mc/compose?to=biola_y2k@yahoo.com>>
>
> >> wrote:
> >> > Hello G.S
> >> >
> >> > How can i make ospf prefer to forward route routes via ospf
> sham-link.
> >> The
> >> > sham link has has a cost of 10 and the routes are coming as IA routes
> >> across
> >> > the MPLS backbone
> >> >
> >> > The router is preferring the backdoor link even when i have increased
> >> the cost
> >> > as high as 65000. The routes are also advertised as IA routes.
> >> >
> >> > Regards,
> >> > Abiola
> >> >
> >> >
> >> > Blogs and organic groups at http://www.ccie.net
> >> >
> >> >
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> >> >
> >> >
> >> >
> >> >
> >> >
> >> >
> >>
> >>
> >>
> >> --
> >> Regards,
> >>
> >>
> >>
> >> Joe Astorino - CCIE #24347
> >> Sr. Technical Instructor - IPexpert
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> --
> Regards,
>
>
>
> Joe Astorino - CCIE #24347
> Sr. Technical Instructor - IPexpert
> Mailto: jastorino@ipexpert.com<http://mc/compose?to=jastorino@ipexpert.com>
> Telephone: +1.810.326.1444
> Live Assistance, Please visit: www.ipexpert.com/chat
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Regards,
Joe Astorino - CCIE #24347
Sr. Technical Instructor - IPexpert
Mailto: jastorino_at_ipexpert.com
Telephone: +1.810.326.1444
Live Assistance, Please visit: www.ipexpert.com/chat
eFax: +1.810.454.0130
IPexpert is a premier provider of Self-Study Workbooks, Video on Demand,
Audio Tools, Online Hardware Rental and Classroom Training for the Cisco
CCIE (R&S, Voice, Security & Service Provider) certification(s) with
training locations throughout the United States, Europe, South Asia and
Australia. Be sure to visit our online communities at
www.ipexpert.com/communities and our public website at www.ipexpert.com
Blogs and organic groups at http://www.ccie.net